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Communication | Regular issue | Vol 4, No. 5, 1976, pp.927-932
Published online, 1st January, 1970
DOI: 10.3987/R-1976-05-0927
Alternative Synthesis of Protoberberine Alkaloid (±)-Xylopinine

Tetsuji Kametani,* Toshio Honda, Toshiji Sugai, and Keiichiro Fukumoto

*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan


Treatment of 2-(2-bromo-4,5-dimethoxybenzoyl)-1,2,3,4-tetrahydro-6,7-dimethoxy-1-methyleneisoquinoline (3) with sodium amide in liquid ammonia afforded the oxoberbine (4) together with the styrene derivative (5) and the hydrolysed product (6). Chlorination of the lactam (4) with phosphoryl chloride gave the chloride, which was then reduced with sodium borohydride to afford (±)-xylopinine (8).
Furthermore, a photolysis of the bromo-enamide (3) also gave the oxoberbine (4) in good yield.